U.S. patent application number 11/858603 was filed with the patent office on 2008-12-11 for color filtering device.
This patent application is currently assigned to YOUNG OPTICS INC.. Invention is credited to Chao-Shun Chen, Mei-Ling Chen, S-Wei Chen, Chun-Fa Hsu, Cheng-Shun Liao, Hung-Cheng Lung.
Application Number | 20080304015 11/858603 |
Document ID | / |
Family ID | 39538618 |
Filed Date | 2008-12-11 |
United States Patent
Application |
20080304015 |
Kind Code |
A1 |
Chen; Mei-Ling ; et
al. |
December 11, 2008 |
COLOR FILTERING DEVICE
Abstract
A color filtering device including a color filter, a plurality
of polarization beam splitting units, a plurality of reflecting
units, and a plurality of wave plates is provided. The color filter
has a plurality of filtering parts and a plurality of light
shielding parts alternately arranged thereon. Each of the
polarization beam splitting units is disposed in front of one of
the filtering parts and makes an angle with a corresponding
filtering part. Each of the reflecting units is disposed in front
of one of the light shielding parts and makes an angle with a
corresponding light shielding part. Each of the wave plates is
substantially parallel to one of the filtering parts. Each of the
polarization beam splitting units is disposed between a pair of a
wave plate and a filtering part. The color filtering device has
both color filtering function and polarization conversion
function.
Inventors: |
Chen; Mei-Ling; (Hsinchu,
TW) ; Chen; S-Wei; (Hsinchu, TW) ; Chen;
Chao-Shun; (Hsinchu, TW) ; Lung; Hung-Cheng;
(Hsinchu, TW) ; Hsu; Chun-Fa; (Hsinchu, TW)
; Liao; Cheng-Shun; (Hsinchu, TW) |
Correspondence
Address: |
J C PATENTS, INC.
4 VENTURE, SUITE 250
IRVINE
CA
92618
US
|
Assignee: |
YOUNG OPTICS INC.
Hsinchu
TW
|
Family ID: |
39538618 |
Appl. No.: |
11/858603 |
Filed: |
September 20, 2007 |
Current U.S.
Class: |
353/20 ;
359/491.01 |
Current CPC
Class: |
G02B 27/285 20130101;
G03B 33/08 20130101; G03B 21/2073 20130101; G03B 21/208 20130101;
G03B 21/14 20130101 |
Class at
Publication: |
353/20 ;
359/483 |
International
Class: |
G02B 5/30 20060101
G02B005/30; G03B 21/14 20060101 G03B021/14 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 11, 2007 |
TW |
96209560 |
Claims
1. A color filtering device, comprising: a color filter, having a
plurality of filtering parts and a plurality of light shielding
parts alternately arranged thereon; a plurality of polarization
beam splitting units, respectively disposed in front of the
filtering parts, each of the polarization beam splitting units
making an angle with a corresponding filtering part; a plurality of
reflecting units, respectively disposed in front of the light
shielding parts, each of the reflecting units making an angle with
a corresponding light shielding part; and a plurality of wave
plates, substantially parallel to the filtering parts respectively,
each of the polarization beam splitting units being disposed
between a pair of a corresponding wave plate and a corresponding
filtering part.
2. The color filtering device as claimed in claim 1, further
comprising a plurality of transparent bodies disposed in front of
the filtering parts and the light shielding parts, wherein a
coating is disposed at a juncture of every two transparent bodies
to form the polarization beam splitting units or the reflecting
units.
3. The color filtering device as claimed in claim 1, wherein the
polarization beam splitting units are substantially parallel to the
reflecting units.
4. The color filtering device as claimed in claim 1, wherein the
angle between each of the polarization beam splitting units and the
corresponding filtering part falls within 0.degree.-90.degree..
5. The color filtering device as claimed in claim 1, wherein the
wave plates are half-wave plates.
6. The color filtering device as claimed in claim 1, wherein the
color filter is rectangular-shaped, and each of the filtering parts
and each of the light shielding parts are substantially
rectangular-shaped.
7. The color filtering device as claimed in claim 1, wherein the
color filter is round, and each of the filtering parts and each of
the light shielding parts are substantially sector-shaped.
8. The color filtering device as claimed in claim 1, wherein colors
of the filtering parts comprise red, green, and blue.
9. The color filtering device as claimed in claim 1, wherein two
neighboring filtering parts have different colors.
10. A color filtering device, suitable for being used in a
projection apparatus, the projection apparatus comprising a lamp
module, a light integration rod, and a light valve, the lamp module
being capable of providing an illumination beam, the light
integration rod being disposed on a transmission path of the
illumination beam and having a light input end and a light output
end, and the light valve being disposed on a transmission path of
the illumination beam and being capable of converting the
illumination beam into an image beam, the color filtering device
comprising: a color filter, having a plurality of filtering parts
and a plurality of light shielding parts alternately arranged
thereon, the color filter being disposed on the transmission path
of the illumination beam and between the light integration rod and
the light valve, and the color filter being capable of being moved
or rotated, so as to make each of the filtering parts face the
light output end of the light integration rod in turn; a plurality
of polarization beam splitting units, respectively disposed in
front of the filtering parts, each of the polarization beam
splitting units making an angle with a corresponding filtering
part; and a plurality of reflecting units, respectively disposed in
front of the light shielding parts, each of the reflecting units
making an angle with a corresponding light shielding part; a
plurality of wave plates, substantially parallel to the filtering
parts respectively, each of the polarization beam splitting units
being disposed between a pair of a corresponding wave plate and a
corresponding filtering part.
11. The color filtering device as claimed in claim 10, wherein an
area of each filtering part is larger than or equal to a
cross-sectional area of the light output end of the light
integration rod.
12. The color filtering device as claimed in claim 10, further
comprising a plurality of transparent bodies disposed in front of
the filtering parts and the light shielding parts, wherein a
coating is disposed at a juncture of every two transparent bodies
to form the polarization beam splitting units or the reflecting
units.
13. The color filtering device as claimed in claim 10, wherein the
polarization beam splitting units are substantially parallel to the
reflecting units.
14. The color filtering device as claimed in claim 10, wherein the
angle between each of the polarization beam splitting units and the
corresponding filtering part falls within 0.degree.-90.degree..
15. The color filtering device as claimed in claim 10, wherein the
wave plates are half-wave plates.
16. The color filtering device as claimed in claim 10, wherein the
color filter is rectangular-shaped, and each of the filtering parts
and each of the light shielding parts are substantially
rectangular-shaped.
17. The color filtering device as claimed in claim 10, wherein the
color filter is round, and each filtering part and each light
shielding part are substantially sector-shaped.
18. The color filtering device as claimed in claim 10, wherein
colors of the filtering parts comprise red, green, and blue.
19. The color filtering device as claimed in claim 10, wherein two
neighboring filtering parts have different colors.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority benefit of Taiwan
application serial no. 96209560, filed on Jun. 11, 2007. All
disclosure of the Taiwan application is incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a color filtering device
and a display apparatus using the same. More particularly, the
present invention relates to a color filtering device having both
color filtering function and polarization conversion function and a
projection apparatus using the same.
[0004] 2. Description of Related Art
[0005] FIG. 1A is a schematic structural view of a conventional
projection apparatus. Referring to FIG. 1A, a conventional
projection apparatus 100 includes an illumination system 110, a
liquid crystal on silicon panel (LCOS panel) 120, and an imaging
system 130. The illumination system 110 includes a lamp module 112,
a light integration rod 114, a color wheel 116 and a polarization
conversion system (PCS) 118. The lamp module 112 emits an
illumination beam 113. The illumination beam 113 passes through the
light integration rod 114, the color wheel 116, the PCS 118 in
sequence and travels to the LCOS panel 120. The LCOS panel 120
converts the illumination beam 113 into an image beam 113' and
makes it project to the imaging system 130. The imaging system 130
includes a plurality of lenses 132, and the imaging system 130
projects the image beam 113' onto a screen (not shown).
[0006] FIG. 1B shows spots formed by the illumination beam
projected onto the PCS and a cross-section of the PCS in FIG. 1A
from top to bottom. Referring to FIGS. 1A and 1B, the PCS 118 has a
light incident surface 118a and a light emitting surface 118b. The
light incident surface 118a has a plurality of transparent regions
119a and a plurality of light shielding regions 119b which are
alternately arranged. Since light rays incident on different
positions of the light integration rod 114 with different angles
are reflected different times in the light integration rod 114, the
illumination beam 113 projects a plurality of spots 113a at
different positions on the light incident surface 118a of the PCS
118. Additionally, since the positions of the spots 113a on the
light incident surface 118a is related to the angles and positions
of the light rays incident on the light integration rod 114, the
spots 113a are not arranged at equal intervals.
[0007] However, as the widths of the transparent regions 119a and
the light shielding regions 119b of the PCS 118 are generally the
same, parts of the spots 113a fall in the light shielding regions
119b and cannot be utilized by the projection apparatus 100 to
project the display image, thus resulting in a loss of brightness
of the display image approaching 15-20%. Furthermore, as a position
tolerance of a lampwick 112a of the lamp module 112 is generated
during manufacturing or assembly, the spots 113a cannot be
accurately focused on the transparent regions 119a, and parts of
the spots 113a fall on the light shielding regions 119b, which
results in a loss of brightness of the display image.
[0008] Referring to FIGS. 1A and 1C, symbol 113b in FIG. 1C
represents spots formed by the illumination beam 113 projected on
the color wheel 116. As the color wheel 116 is composed of a
plurality of filtering parts 116a with different colors, and in a
period from Time T1 at which a juncture 116b of two neighboring
filtering parts 116a passes by the left end of a horizontal line
113b' of the spot 113b to Time T2 at which the juncture 116b passes
by the right end of the horizontal line 113b', the horizontal line
113b' falls on the filtering parts 116a with two different colors
at the same time, light with two different colors are generated.
Accordingly, in the period from Time T1 to Time T2, the LCOS panel
120 does not perform image processing, which results in the
decrease of brightness of the display image. Referring to FIG. 1D,
similarly, the same problem also occurs in a period from Time T3 at
which the juncture 116b passes by the right end of a horizontal
line 113b'' of the spot 113b to Time T4 at which the juncture 116b
passes by the left end of the horizontal line 113b''.
[0009] Another conventional projection apparatus uses two fly eyes
to replace the above light integration rod 114 to provide a light
uniform function. However, an alignment tolerance is generated when
the two fly eyes is assembled, so the spots formed by the
illumination beam imaged on the PCS cannot be accurately focused on
the transparent regions after the illumination light passes through
the fly eyes, which also results in the loss of brightness of the
display image.
SUMMARY OF THE INVENTION
[0010] Accordingly, the present invention is directed to a color
filtering device, which has both color filtering function and
polarization conversion function, and a projection apparatus using
the color filtering device projects display images with higher
brightness.
[0011] Other advantages of the present invention can be further
apparent from the technical features disclosed in the present
invention. As embodied and broadly described herein, a color
filtering device including a color filter, a plurality of
polarization beam splitting units, a plurality of reflecting units
and a plurality of wave plates is provided in an embodiment of the
present invention. The color filter has a plurality of filtering
parts and a plurality of light shielding parts. The filtering parts
and the light shielding parts are alternately arranged. The
polarization beam splitting units are disposed in front of the
filtering parts respectively, and each of the polarization beam
splitting units makes an angle with a corresponding filtering part.
The reflecting units are respectively disposed in front of the
light shielding parts, and each of the reflecting units makes an
angle with a corresponding light shielding part. The wave plates
are substantially parallel to the filtering parts respectively, and
each of the polarization beam splitting units is disposed between a
pair of a corresponding wave plate and a corresponding filtering
part.
[0012] A color filtering device suitable for being used in a
projection apparatus is further provided in an embodiment of the
present invention. The projection apparatus includes an
illumination system and a light valve. The illumination system
includes a lamp module, a light integration rod, and the
above-mentioned color filtering device. The lamp module is capable
of providing an illumination beam. The light integration rod is
disposed on a transmission path of the illumination beam and has a
light input end and a light output end. The color filter is
disposed on the transmission path of the illumination beam and
between the light integration rod and the light valve. Furthermore,
the color filter is capable of being moved or rotated, so as to
make each filtering part face the light output end of the light
integration rod in turn. The light valve is disposed on the
transmission path of the illumination beam, and the light valve is
capable of converting the illumination beam into an image beam.
[0013] As the color filtering device integrates the color filter,
the polarization beam splitting units, the reflecting units and the
wave plates, the color filtering device has both color filtering
function and polarization conversion function. Moreover, in the
projection apparatus, since one of the filtering parts is moved to
a position right facing the light output end of the light
integration rod at a moment, the proportion of the illumination
beam passing through the color filtering device is greatly
increased. In this manner, the brightness of the display image
projected by the projection apparatus is effectively improved.
[0014] Other objectives, features and advantages of the present
invention will be further understood from the further technological
features disclosed by the embodiments of the present invention
wherein there are shown and described preferred embodiments of this
invention, simply by way of illustration of modes best suited to
carry out the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The accompanying drawings are included to provide a further
understanding of the invention, and are incorporated in and
constitute a part of this specification. The drawings illustrate
embodiments of the invention and, together with the description,
serve to explain the principles of the invention.
[0016] FIG. 1A is a schematic structural view of a conventional
projection apparatus.
[0017] FIG. 1B shows spots formed by the illumination beam
projected onto the PCS and a cross-section of the PCS in FIG. 1A
from top to bottom.
[0018] FIGS. 1C and 1D show spots formed by the illumination beam
in FIG. 1A projected on a color wheel.
[0019] FIG. 2A is a perspective view of a color filtering device
according to an embodiment of the present invention.
[0020] FIG. 2B is a cross-sectional view of the color filtering
device in FIG. 2A taken along line A-A.
[0021] FIG. 2C is another perspective view of a color filtering
device according to an embodiment of the present invention.
[0022] FIG. 3 is a perspective view of a color filtering device
according to another embodiment of the present invention.
[0023] FIG. 4 is a schematic structural view of a projection
apparatus according to an embodiment of the present invention.
[0024] FIG. 5 is a schematic structural view of a projection
apparatus according to another embodiment of the present
invention.
DESCRIPTION OF EMBODIMENTS
[0025] In the following detailed description of the preferred
embodiments, reference is made to the accompanying drawings which
form a part hereof, and in which is shown by way of illustration
specific embodiments in which the invention may be practiced. In
this regard, directional terminology, such as "top," "bottom,"
"front," "back," etc., is used with reference to the orientation of
the Figure(s) being described. The components of the present
invention can be positioned in a number of different orientations.
As such, the directional terminology is used for purposes of
illustration and is in no way limiting. On the other hand, the
drawings are only schematic and the sizes of components may be
exaggerated for clarity. It is to be understood that other
embodiments may be utilized and structural changes may be made
without departing from the scope of the present invention. Also, it
is to be understood that the phraseology and terminology used
herein are for the purpose of description and should not be
regarded as limiting. The use of "including," "comprising," or
"having" and variations thereof herein is meant to encompass the
items listed thereafter and equivalents thereof as well as
additional items. Unless limited otherwise, the terms "connected,"
"coupled," and "mounted" and variations thereof herein are used
broadly and encompass direct and indirect connections, couplings,
and mountings. Similarly, the terms "facing," "faces" and
variations thereof herein are used broadly and encompass direct and
indirect facing, and "adjacent to" and variations thereof herein
are used broadly and encompass directly and indirectly "adjacent
to". Therefore, the description of "A" component facing "B"
component herein may contain the situations that "A" component
facing "B" component directly or one or more additional components
is between "A" component and "B" component. Also, the description
of "A" component "adjacent to" "B" component herein may contain the
situations that "A" component is directly "adjacent to" "B"
component or one or more additional components is between "A"
component and "B" component. Accordingly, the drawings and
descriptions will be regarded as illustrative in nature and not as
restrictive.
[0026] Referring to FIGS. 2A and 2B, a color filtering device 200
according to an embodiment of the present invention includes a
color filter 210, a plurality of polarization beam splitting units
220, a plurality of reflecting units 230 and a plurality of wave
plates 240. The color filter 210 has a plurality of filtering parts
212 and a plurality of light shielding parts 214. The filtering
parts 212 and the light shielding parts 214 are alternately
arranged. Each of the polarization beam splitting units 220 is
disposed in front of the filtering parts 212 respectively, and each
of the polarization beam splitting units 220 makes an angle .theta.
with a corresponding filtering part 212. Each of the reflecting
units 230 is disposed in front of the light shielding parts 214
respectively, and each of the reflecting units 230 makes an angle
.phi. with a corresponding light shielding part 214. The wave
plates 240 are substantially parallel to the filtering parts 212
respectively, and each of the polarization beam splitting units 220
is disposed between a pair of a corresponding wave plate 240 and a
corresponding filtering part 212.
[0027] In this embodiment, the color filtering device 200 further
includes a plurality of transparent bodies 250 disposed in front of
the filtering parts 212 and the light shielding parts 214. Each of
the transparent bodies 250 comprises two triangular prisms 252a and
252b, and a coating is disposed at a juncture of the triangular
prism 252a of each transparent body 250 and the triangular prism
252b of a neighboring transparent body 250, so as to form the
polarization beam splitting units 220 and the reflecting units 230.
Also, as shown in FIG. 2C, a transparent body 250 is made of a
transparent material in the shape of a trapezohedron, and a
polarization beam splitting film and a reflecting film are
respectively coated at the junctures of the transparent body 250
and its neighboring transparent bodies 250. In detail, the coating
disposed in front of the filtering parts 212 is the polarization
beam splitting film, and the polarization beam splitting units 220
are polarization beam splitting films. The coating disposed in
front of the light shielding parts 214 is a reflecting film, and
the reflecting units 230 are reflecting films. In other
embodiments, the polarization beam splitting units may be
polarization beam splitter plates, and the reflecting units may be
reflector plates. Under such circumstance, the color filtering
device does not need the transparent body.
[0028] In this embodiment, the color filter 210 is, for example,
rectangular-shaped, and each of the filtering parts 212 and each of
the light shielding parts 214 are, for example, also
rectangular-shaped. Furthermore, the filtering parts 212 have
various colors, and any two neighboring filtering parts 212 have
different colors. In details, in this embodiment, the filtering
parts 212 are further classified into red filtering parts 212a,
green filtering parts 212b, and blue filtering parts 212c according
to colors.
[0029] As shown in FIG. 2B, the color filtering device 200 in this
embodiment has both color filtering function and polarization
conversion function. For example, when an un-polarized beam (white
beam) 50 is incident on the red filtering part 212a of the color
filtering device 200, the unpolarized beam 50 is filtered into a
red beam. Next, the un-polarized beam 50 propagates to the
polarization beam splitting unit 220. The polarization beam
splitting unit 220 divides the unpolarized beam 50 into a first
polarized beam 50a and a second polarized beam 50b. The first
polarized beam 50a is reflected to the reflecting unit 230 by the
polarization beam splitting unit 220, and is then reflected by the
reflecting unit 230. Moreover, the second polarized beam 50b passes
through the polarization beam splitting units 220 and propagates to
the wave plates 240, and the wave plates 240 convert the second
polarized beam 50b into a beam with the same polarization direction
of the first polarized beam 50a. The first polarized beam 50a
passing through the wave plates 240 combines with the first
polarized beam 50a reflected by the reflecting units 230.
Furthermore, the polarization direction of the first polarized beam
50a is substantially perpendicular to that of the second polarized
beam 50b, and the wave plates 240 are, for example, half-wave
plates. In detail, the first polarized beam 50a is an S-polarized
beam, and the second polarized beam 50b is a P-polarized beam.
[0030] In this embodiment, the polarization beam splitting units
220 are substantially parallel to the reflecting units 230
respectively, so as to allow the second polarized beam 50b passing
through the polarization beam splitting units 220 and the first
polarized beam 50a reflected by the reflecting units 230 to be
emitted from the color filtering device 200 substantially in the
same direction. Furthermore, the angle .theta. and the angle .phi.
fall within, for example, 0.degree.-90.degree., and preferably
45.degree.. In addition, the wave plates 240 are also substantially
parallel to the filtering parts 212, for example.
[0031] From the above description, the unpolarized beam (white
beam) 50 incident on the red filtering parts 212a of the color
filtering device 200 is converted into a red beam with a first
polarization direction by the color filtering device 200 after
passing through the color filtering device 200. Similarly, the
unpolarized beam (white beam) 50 incident on the green filtering
parts 212b of the color filtering device 200 is converted in to a
green beam with the first polarization direction by the color
filtering device 200 after passing through the color filtering
device 200. The unpolarized beam (white beam) 50 incident on the
blue filtering parts 212c of the color filtering device 200 is
converted into a blue beam with the first polarization direction by
the color filtering device 200 after passing through the color
filtering device 200.
[0032] The color filtering device 200 in this embodiment has both
color filtering function and polarization conversion function.
Moreover, the color filtering device 200 replaces the color wheel
and the polarization conversion unit in the conventional projection
apparatus. That is to say, one element in this embodiment replaces
two elements in the conventional art. Therefore, the optical path
of a projection apparatus using the color filtering device 200 is
reduced, thereby reducing the volume of the projection
apparatus.
[0033] It should be noted that the color filter 210 is not limited
to be rectangular-shaped, and the color filtering device 200 is not
limited to be cuboid in the present invention. In other embodiments
of the present invention, the color filter and the color filtering
device can also be in other suitable shapes. For example, in a
color filtering device 200' according to another embodiment of the
present invention, referring to FIG. 3, a color filter 210' is
round, and each of the filtering parts 212' and each of the light
shielding parts 214' are sector-shaped. Further, the polarization
beam splitting units 220', reflecting units 230', transparent
bodies 250', and wave plates 240' are also in the shape
corresponding to that of the filtering parts 212' or the light
shielding parts 214', so that the color filtering device 200' is in
the shape of disk.
[0034] Referring to FIG. 4, a projection apparatus 300 according to
an embodiment of the present invention includes an illumination
system 310, a light valve 320 and an imaging system 330. The
illumination system 310 includes a lamp module 312, a light
integration rod 314 and the above color filtering device 200. The
lamp module 312 is capable of providing an illumination beam 313.
The light integration rod 314 is disposed on the transmission path
of the illumination beam 313 and has a light input end 314a and a
light output end 314b. The color filtering device 200 is disposed
on the transmission path of the illumination beam 313 and is
disposed at the position facing the light output end 314b.
Moreover, the color filtering device 200 is, for example,
electrically connected to an actuator (not shown). The actuator is
capable of making the color filtering device 200 move to-and-fro in
a direction C, so as to make one of the red filtering parts 212a,
the green filtering parts 212b and the blue filtering parts 212c
facing the light output end 314b. The light valve 320 is disposed
on the transmission path of the illumination beam 313, and the
color filtering device 200 is disposed between the light
integration rod 314 and the light valve 320. The light valve 320
is, for example, the LCOS panel, which is capable of converting the
illumination beam 313 into an image beam 313'. The imaging system
330 is disposed on the transmission path of the image beam 313'. In
this embodiment, the imaging system 330 further includes a
plurality of lenses 332, and the imaging system 330 is used to
project the image beam 313' onto a screen.
[0035] In this embodiment, in each cycle of the to-and-fro movement
of the color filtering device 200, the color of the filtering parts
212 facing the light output end 314b is, for example, red, green,
blue, blue, green and red in sequence. In detail, each cycle
includes two frame times, the display image in the first frame time
is formed by overlapping the red, green and blue image beams 313',
and the display image in the second frame time is formed by
overlapping the blue, green and red image beams 313'.
[0036] As the light output end 314b merely faces one of the
filtering parts 212 at a time, most of the illumination beam 313
output from the light output end 314b enters the color filtering
device 200 through said one of the filtering parts 212.
Furthermore, the light valve 320 performs the on/off switch on the
liquid crystal when the illumination beam 313 is incident on the
light shielding parts 214 by means of the match between the
frequencies of the actuator and light valve 320, which effectively
utilizes time intervals. Compared with conventional projection
apparatus in which a larger proportion of the illumination beam is
blocked by the light shielding region of the PCS, the projection
apparatus 300 of this embodiment has higher light utilization
efficiency, so it projects display images with higher
brightness.
[0037] In this embodiment, in order to ensure that all light rays
of the illumination beam 313 output from the light integration rod
314 can pass through the filtering parts 212 facing the light
integration rod 314, the cross-sectional area of the light output
end 314b may be designed to be smaller than or equal to the area of
each filtering part 212. Additionally, the light output end 314b
may be put close to the color filtering device 200 to some suitable
extent, so as to ensure that most of the illumination beam 313 can
pass through the filtering parts 212 facing the light integration
rod 314. In this way, the light utilization efficiency of the
projection apparatus 300 is greatly improved. Moreover, the area of
the filtering parts 212 may be designed to be somewhat larger than
the cross-sectional area of the light output end 314b. As such, the
situation that parts of the illumination beam 313 cannot pass
through the filtering parts 212 facing the light integration rod
314 due to the assembly tolerance of the lampwick 312a of the lamp
module 312 or each element of the projection apparatus 300 can be
avoided. In other words, the position error of the projection
apparatus 300 as a result of assembly does not influence the
brightness of the display image.
[0038] Moreover, in this embodiment, the color filtering device 200
is linearly moved, and the filtering parts 212 is
rectangular-shaped rather than sector-shaped, and thus the
situation that the light with two different colors are generated in
the same horizontal line 113b' in FIG. 1C is avoided. Accordingly,
the light valve 320 is unnecessary to be closed in a specific time
as that in the conventional art, so the light utilization
efficiency of the projection apparatus 300 of this embodiment is
improved.
[0039] It should be noted that the light valve 320 is not limited
to a LCOS panel in the present invention. In other embodiments, the
light valve can also be a transmissive liquid crystal panel.
Definitely, those of ordinary skills in the art should appreciate
that the position of the imaging system 330 should be properly
adjusted in the embodiments adopting the transmissive liquid
crystal panel, which will not further illustrated with
drawings.
[0040] Referring to FIG. 5, a projection apparatus 300' according
to another embodiment of the present invention is similar to the
projection apparatus 300 (referring to FIG. 4) of the above
embodiment, except for the differences described as follows. The
projection apparatus 300' adopts the above color filtering device
200' (referring to FIG. 3). Referring to FIGS. 3 and 5 together, in
this embodiment, the color filtering device 200' is, for example,
connected to a motor (not shown). The motor drives the color
filtering device 200' to rotate in a rotation direction E, such
that the filtering parts 212a', 212b' and 212c' face the light
output end 314b in turn. In this way, the projection apparatus 300'
of this embodiment has the similar functions as those of the
projection apparatus 300. However, the color filtering device 200'
of the present invention is not limited to rotate in the rotation
direction E. In other embodiments, the color filtering device may
also rotate in an inverse direction of the rotation direction
E.
[0041] In view of above, as the color filtering device of the
present invention integrates the color filter, the polarization
beam splitting units, the reflecting units and the wave plates, the
color filtering device of the present invention has both color
filtering function and polarization conversion function. Therefore,
the color filtering device of the present invention replaces the
color wheel and the polarization conversion unit in the
conventional projection apparatus. That is, one element in the
present invention replaces two elements in the conventional art.
Thus, the optical path of the projection apparatus using the color
filtering device is reduced, thereby reducing the volume of the
projection apparatus.
[0042] Additionally, in the projection apparatus of the present
invention, as the color filtering device is capable of being moved
or rotated to allow one of the filtering parts to face the light
output end of the light integration rod in turn, the proportion of
the illumination beam passing through the color filtering device is
greatly increased. In this way, the brightness of the display image
projected by the projection apparatus is effectively improved.
Additionally, the cross-sectional area of the light output end can
be designed to be smaller than or equal to the area of each
filtering part to increase the proportion of the illumination beam
passing through the filtering parts facing the light integration
rod. In this manner, the light utilization efficiency of the
projection apparatus of the present invention is greatly improved,
and the brightness of the display image does not be easily
influenced by the assembly error of the projection apparatus.
[0043] The foregoing description of the preferred embodiment of the
invention has been presented for purposes of illustration and
description. It is not intended to be exhaustive or to limit the
invention to the precise form or to exemplary embodiments
disclosed. Accordingly, the foregoing description should be
regarded as illustrative rather than restrictive. Obviously, many
modifications and variations will be apparent to practitioners
skilled in this art. The embodiments are chosen and described in
order to best explain the principles of the invention and its best
mode practical application, thereby to enable persons skilled in
the art to understand the invention for various embodiments and
with various modifications as are suited to the particular use or
implementation contemplated. It is intended that the scope of the
invention be defined by the claims appended hereto and their
equivalents in which all terms are meant in their broadest
reasonable sense unless otherwise indicated. Therefore, the term
"the invention", "the present invention" or the like is not
necessary limited the claim scope to a specific embodiment, and the
reference to particularly preferred exemplary embodiments of the
invention does not imply a limitation on the invention, and no such
limitation is to be inferred. The invention is limited only by the
spirit and scope of the appended claims. The abstract of the
disclosure is provided to comply with the rules requiring an
abstract, which will allow a searcher to quickly ascertain the
subject matter of the technical disclosure of any patent issued
from this disclosure. It is submitted with the understanding that
it will not be used to interpret or limit the scope or meaning of
the claims. Any advantages and benefits described may not apply to
all embodiments of the invention. It should be appreciated that
variations may be made in the embodiments described by persons
skilled in the art without departing from the scope of the present
invention as defined by the following claims. Moreover, no element
and component in the present disclosure is intended to be dedicated
to the public regardless of whether the element or component is
explicitly recited in the following claims.
* * * * *